Optimization of Continuous Granular Flow in a Helical Screw Induced Rotation Fluidized Bed Reactor: Cold Test Insights on Multi Parameter Control

Abstract

This study investigates the Residence Time Distribution (RTD) behavior in a Helical Screw Reactor (HSR) by analyzing key performance indicators, including Mean Residence Time (MRT), average outlet flow rate (Ave_out), and Reynolds number (N_Re). Using a structured Design of Experiments (DOE) approach integrated with Response Surface Methodology (RSM), the influence of Feed Rate Speed (FRS) and Helical Screw Rotation Speed (HSRS) on reactor behavior was statistically examined. Results reveal that FRS has a significant effect on Ave_out (F = 873.24, p < 0.0001), whereas HSRS shows negligible influence (p = 0.3673). Interaction effects (FRS × HSRS) were statistically insignificant (p = 0.5966). A notable quadratic effect was observed for FRS (F = 9.67, p = 0.0171), indicating nonlinearity in its influence on Ave_out. The MRT model was statistically significant (F = 4.55, p = 0.0363), confirming that the selected factors sufficiently explain MRT variability. N_Re was strongly impacted by experimental parameters (F = 132.66, p < 0.0001), highlighting their critical role in reactor hydrodynamics. Perturbation plots demonstrated MRT and N_Re high sensitivity to FRS variations compared to HSRS. Model validation through diagnostic plots (normal Q-Q and residuals vs. factors) confirmed good model fit and random error distribution. These findings underscore the capability to finetune HSR reactor performance by optimizing FRS and HSRS, thereby enhancing mass transfer, mixing efficiency, and biomass feed consistency in thermochemical applications. This predictive modeling approach offers a valuable optimization framework for advancing continuous biomass conversion systems and improving the sustainability and efficiency of energy processes.